The RSM-40 "Vysota"
is a submarine launched intercontinental ballistic missile complex based
around the R-29 missile. Development of this missile was approved on 28
September 1964. Missile is deployed on the "Murena" class
submarines since 1973. It is also known as SS-N-8 "Sawfly" with
NATO countries.

It is a double-stage missile
powered by a liquid-propellant. The RSM-40 carries a single nuclear
warhead. Missile also carries defense countermeasures. It was the first
Soviet submarine launched intercontinental ballistic missile using a
digital computer and inertial guidance with astrocorrection for improved
accuracy.

The first ground-based
launch was made in 1969. The first sea launch - in 1971. The first "Murena"
class submarine with the RSM-40 missiles onboard was detected by US
intelligence in August 1972. Initial operational capability was reached in
1973 and in 1974 eighteen "Murena" class ("Delta I")
submarines with the RSM-40 missiles were operational.

Overall there were developed
three modifications of the RSM-40 including the basic R-29 missile. It's
improved variant with extended range is the R-29D. One more variant is the
R-29U featuring very similar characteristics with the R-29D. The last
mentioned R-29D became operational in 1978 and was intended for the "Murena-M"
submarines, carrying 16 missiles instead of 12 missiles, carried by "Murena's".
Later all "Murena" class submarines were reequipped with
improved missiles.

Missiles long range of fire
allowed submarine to avoid passing through the US sonar barriers as they
could launch missiles from the distance close to their bases. The RSM-40
are launched from the submerged submarine with an interval in 7 seconds.
Submarine's normal preparation to launch missiles time is 15 minutes,
while under conditions of alert this time is only one minute. Missiles are
fired from submerged or moored at it's base submarine.

In 1991 Russia operated 4 "Murena-M"
submarines with 64 RSM-40 missiles and 9 "Murena" submarines
with 108 RSM-40 in the Northern fleet and 9 "Murena's" with 108
similar missiles in the Pacific fleet. These were operational submarines
not including reserve units. Furthermore there are no data about RSM-40
missiles operational with the Baltic and Black See fleet.